This invention relates to a venting device for a foam mold for example for urethane foam. More particularly it relates to a venting device capable of sufficiently exhausting air and reaction product gases in a cavity of a foam mold and simultaneously effectively preventing a foaming material from extending from vent holes of the foam mold.
Hitherto used venting devices for foam molds have been disclosed for example in Japanese Utility Model Application Laid-open Nos. 62-154,908 and 61-158,412 and Japanese Patent Laid-open No. 60-257,211.
In the Japanese Utility Model Application Laid-open No. 62-154,908, spot facings are provided at vent holes formed in an upper mold half of a foam mold, thereby making easy removal of protrusions of a foamed product which have extended from the vent holes and hardened. In the Japanese Utility Model Application Laid-open No. 61-158,412, vent holes provided in an upper mold half are closed by plugs when upper and lower mold halves are closed together. In the Japanese Patent Application Laid-open No. 60-257,211, protrusions of a foamed product extended from vent holes of an upper mold half are removed by mechanically scratching them.
In the first disclosed feature, however, it would take a lot of man-hours for the removal of the protrusions of the foamed product. What is worse still it is very difficult to completely remove the protrusions of the foamed product. This also hold true in the third disclosed feature. It is in practice impossible to remove all protrusions completely by simple scratching.
In the second disclosed feature, moreover, it is difficult to obtain an accuracy for exactly inserting all the plugs into vent holes. In most cases, the plugs and the vent holes are not in alignment with each other.